Dehydrators contain several stacked trays, not unlike bamboo steamer baskets. Heated air flows through all the layers and dries food evenly. An adjustable thermostat controls the temperature, and you can dehydrate slices of fruit, vegetables, herbs, or even meat to make jerky.
These little gadgets are much more efficient than using an oven in terms of both time and energy. You can also adjust and maintain the temperature of a dehydrator much more precisely, important for low-temperature drying and preserving vitamins and minerals in the food.
The one thing I wonder is how often I'll really use a dehydrator. I worry that it will just sit in the cupboard for months between use. Or maybe once I have one, I'll find myself using it all the time. It's hard to predict.
Dehydrators run from about $40 to about $60, though you can certainly find more expensive professional models if you're so inclined. Take a look at these models:
Do you have a food dehydrator? How often do you use it?